1. Field of the Invention
The present invention relates to a bacterial eliminator for killing bacteria (including viruses) contained in water delivered from water supply means such as a water main.
2. Description of the Related Art
The fact that ultra-violet light has a bacteria eliminating effect is well known. It is therefore possible to propose a water purifier having sterilizing effect by incorporating an ultraviolet lamp into a mains water supply apparatus.
However, an ultraviolet lamp generates ultraviolet light using electrons in mercury gas due to thermoelectron discharge from a filament.
Accordingly, a conventional ultraviolet lamp requires time until temperature is raised to cause thermoelectron discharge. In ultraviolet lamps of the type using electric discharge also, a certain amount of time is required until discharge occurs and ultraviolet light is generated.
In a bacterial eliminator using an ultraviolet lamp, if water flows before lighting the ultraviolet lamp (namely before sufficiently generating ultraviolet light), water that has not been subjected to bacteria removal will be supplied. For this reason, in order to use an ultraviolet lamp in a bacteria eliminator, it is necessary have the lamp normally lit, regardless of whether water is flowing or not.
However, if the lamp is kept lit, when there is no water flow, water around the lamp is heated by the lamp. Therefore the cooling effect of the water is reduced and the temperature of the lamp itself rises.
After that, if a tap is opened and water flows, the lower temperature water comes into contact with the lamp. If that happens, there is a potential problem of the lamp being damaged. Therefore, if an ultraviolet lamp is to be used in a bacteria eliminator, it is necessary to have a separate structure and material for avoiding damage to the lamp and there is a problem that the device will become large in size and expensive.
The present invention has been conceived in view of the above described situation and an object of the invention is to provide a bacteria eliminator suitable for size reduction and cost reduction.